1986 2WD 7.5" 3.58 differentail and have some play in the pinion gear at the drive shaft connection. IT's not u-joints. It has 413,000 miles so could be worn front bearing, but I heard a pinion gear nut can back off. Is a backed off pinion gear nut a common occurance on these Toyota differentials? Just curious to get an idea what I might be up against in repairs. Thanks

 

They are staked in there pretty hard from the factory, but it is very easy to check. Just pull the drive shaft and the pinion nut is exposed right there.

 

I just had to tighten mine up a few days ago. The truck would start shaking pretty bad. I mean bad enough you could hear my metal watch band on my wrist make noise, when letting off the gas at 50+mph, or when hitting the clutch at or around those speeds. This caused the differential to "unload" and the pinion gear to wobble, thus making the drive shaft wobble, on up into the transfer case. All i did was take the drive shaft off, and tighten up the pinion nut with a 1/2" drive ratchet, and the appropriate size socket. Then hit the nut with a cold chisel to "ping" one side of the nut over where the slotted key groove is on the pinion gear. Threw in a new pinion seal while i was at it. Vibration is now gone, drive shaft is no longer wobbling. I have no idea what the torque spec is. I went off of German torque spec. "Goodntight"